Gear should be tailored towards the mission, if you are fighting your kit there is a problem.
On one end of the spectrum we have the guy who has so much s**t on his vest that he looks like the Michelin man, and has his AR decked out with cheap airsoft rails, fakepoint, a 20 dollar sealcommando brand flashlight and a crummy nylon holster strapped around his knee, on the other end of the spectrum we have the guy who throws mags in his pockets and never does any practical shooting besides static shooting at the benchrest.
If I am doing drills with my AR I will wear my fragvest, plates, camelback, my own chestrig, sometimes my helmet.
Alot of issued load bearing kit, ie the issued "tactical vest" is fine for running around with no armor on with five mags of blanks and sockies and chocky bars stuffed in the pockets, but once you throw on a fragvest with plates and a realistic load out its useless (hey much like the smallpack and new ruck). Its a pos that is too bulky for what it carries. Ya im bitter

Ive been much happier wearing my Hellcat mk3 (which carries much more ammo then the issued vest without the bulk) and RAID pack.
On an AR all you realistically need is: a vickers sling, surefire, BUIS, optic, rail system, vertical grip and an IR Laser

. You should not be running with irons only as they are slower and difficult to shoot with on the move and don't allow you to discriminate targets at a distance.
If I am just doing a fun shoot ie plinking away with my Ruger 1022 or ruger mk2, or enjoying my milsurps I don't wear any kit at all.
For hunting im not battling hordes of killer rabbits and rabid deer so simply dropping mags in my smock/parka is sufficient.
If I were a civilian shooter training for zombies/home defense or just looking for something practical to shoot with I would probably wear a manbag or a simple molle belt with a few mag pouches, med kit, dump bag, and a holster. But that's just me, if you are comfortable and efficient with a chest rig/vest then go right ahead.